Conversion Finance vs New Build: Which Funding Fits?

Conversion finance is usually the quicker, lighter route when a building already stands and the works are mostly internal. New build finance suits ground-up schemes, where the lender funds construction in stages against a fuller programme of risk. The right answer for a project in England depends on four things: how the lender sees planning risk, how the VAT works out, how heavy the works are, and how you plan to exit. This guide takes each in turn.

It is written for developers, investors and professional landlords. If you are a homeowner financing a loft or kitchen extension, the products and underwriting below are not designed for you.

TL;DR

• Conversions and new builds are underwritten differently, even when the finished asset is identical. Lenders weigh planning risk, build risk and your track record in different proportions.
• VAT can swing the numbers: new qualifying dwellings are generally zero-rated, while qualifying conversions can attract a reduced 5% rate instead of 20%.
• “Light” and “heavy” refurbishment are lender labels, not legal ones. Where your scheme falls decides whether a bridging loan or a staged development facility fits.
• Plan the exit before you apply. A conversion that ends as a long-term let must pass buy-to-let tests, which differ from development underwriting.

Table of Contents

• What the two routes actually mean
• How lenders see the risk differently
• Planning: the gate before the finance
• VAT: the quiet difference in your appraisal
• Light versus heavy refurbishment
• Side by side: conversion versus new build
• Planning the exit before you borrow
• Our view: match the structure to the unknowns
• Choosing between the two: a practical checklist
• Working with us
• FAQ
• Sources

What the two routes actually mean

Conversion finance funds the purchase of an existing building and the works to change its use or layout: offices into flats, a large house into two or three apartments, a shop with accommodation above into residential units. It is typically short-term, and the structure depends on how much work is involved.

New build finance (development finance) funds a ground-up scheme: land purchase, then construction costs released in stages as the build progresses, usually monitored by a surveyor. You can read more on how that works in our guide to why developers use development finance in the UK.

The distinction matters because the lender is not pricing the finished product. It is pricing the journey to it: what can go wrong, how long it takes, and who is steering.

How lenders see the risk differently

A building that already exists removes some uncertainties: foundations, ground conditions and the structure are visible. A new build removes others: there is no hidden defect in a wall you have not built yet. Neither is simply safer.

What lenders really care about is the unknown. On conversions, that is often planning route and structural surprises. On new builds, it is cost inflation, programme delay and contractor performance.

A recent piece in The Intermediary makes a point we see regularly: some lenders apply conservative planning-risk assumptions to every project, while others who know permitted development well treat those conversions as lower-risk, lighter refurbishments. The same scheme can therefore get a very different response depending on who you ask. Assuming a “simple” permitted development conversion will automatically attract cheaper money is a common and costly mistake.

The other recurring trap is experience. A first-time developer taking on a conversion can be declined for lack of development track record by a lender that would have been comfortable with a lighter scheme. Matching the project to the right credit appetite is most of the job.

Planning: the gate before the finance

Both routes start with the same question: is there permission, or do you need it? The government’s guidance on when permission is required explains that planning permission is needed where work meets the statutory definition of development, which includes building operations and material changes of use.

For conversions, permitted development can remove the need for a full planning application. Under Class MA, the Intermediary reports, a landlord who owns shops, an office block or a redundant commercial unit can convert it into flats without a full application. That is a major reason conversion has become a focus for investors. It does not remove the need for prior approval steps, building regulations or lender diligence.

For new builds, you will almost always need full or outline planning permission before a development lender releases funds, and often a clear route through conditions. A site with consent can attract better terms than one without; a site without consent is typically a bridging conversation first.

What happens if work goes ahead without approval

This is a financing issue as much as a legal one. Councils can issue enforcement notices that require unauthorised work to be reversed, which means demolishing an extension or reverting a conversion at the owner’s expense. Retrospective building control, known as regularisation, is possible, but Oxford City Council’s guidance is clear that it is not a guarantee of compliance: inspection may demand remedial work or opening up finished structures. Regularisation only covers work started after 11 November 1985 that fell within the scope of the Building Regulations.

A lender will not want to take security over a building with that cloud on it, and a buyer’s solicitor will find it. If you want to understand how a completion certificate fits into the picture, this explainer on loft conversion regulations and completion certificates covers the practical side for residential works.

VAT: the quiet difference in your appraisal

VAT rarely appears in the first conversation and often decides the margin. HMRC’s VAT Notice 708 sets out the position:

The consequence for your cash flow is real. On a new build you generally pay no VAT on the qualifying construction. On a qualifying conversion you pay 5% rather than 20%, which is still a cost you must fund during the project, and which may or may not be recoverable depending on your structure.

If you are building or converting a home for yourself, HMRC runs a separate scheme. The guidance on VAT refunds for DIY housebuilders covers conversions of existing buildings into dwellings, and the page on reclaiming VAT on a self build home covers new homes. Eligibility is specific, so check the criteria before you build the refund into a facility. This scheme is for people creating their own home, not a route for commercial developers selling on.

Tax treatment depends on your circumstances, so have your accountant confirm the VAT position before the appraisal goes to a lender.

Light versus heavy refurbishment

This is where conversion finance splits in two. Lenders use the terms loosely, and definitions vary by lender, so treat the following as the general pattern rather than a rulebook.

Light refurbishment generally means works that do not change the structure, layout or use of the building: decorating, new kitchens and bathrooms, flooring, rewiring and similar. Many bridging lenders will fund these on a straightforward basis, often with the works costs released after the initial advance rather than monitored through a full build programme.

Heavy refurbishment generally involves structural alterations, a change of use, adding units or extending. That pushes the project towards development-style underwriting: a detailed schedule of works, a contractor, a monitoring surveyor, staged drawdowns and a lender who wants to see experience.

The boundary matters because it changes the product, the speed and the cost. A scheme described as light that turns out to need structural work mid-project can break the facility terms. Describe it honestly at the outset and choose the structure to match. Our page on bridging finance covers the shorter, lighter end, and development finance covers the heavier end, including mezzanine and joint venture equity where the senior debt does not stretch far enough.

Side by side: conversion versus new build

The table is a general guide. Individual schemes cut across it: a derelict building needing full structural rebuild behaves more like a new build than a light conversion.

Planning the exit before you borrow

Both routes fail most often at the end. The two exits are sale and refinance.

Sale. The lender wants evidence that the units will sell at the values in your appraisal, within the term. Conversions into flats can raise questions about unit sizes, parking and the local market, so evidence from comparable sales carries weight.

Refinance to a long-term let. This is where landlords tend to get caught. A conversion does not roll neatly into a buy-to-let mortgage. As MoneyHelper explains, most buy-to-let mortgages are interest-only, and lenders test the rent against the repayments. Industry commentary puts rental coverage ratios typically in the range of 125% to 145% of the payment, though each lender sets its own test. A property can look fine on a development appraisal and still fail those criteria. Work the numbers backwards from the buy-to-let test before you commit to the conversion.

If the plan is to hold, our buy-to-let mortgage team can sanity-check the exit at the start, and for larger stabilised assets a commercial mortgage may suit better.

Our view: match the structure to the unknowns

We arrange finance for developers and investors every week, and the same pattern repeats. The deals that struggle are rarely the ones with a weak asset. They are the ones where the funding structure was chosen before the risks were understood.

Our view, in short:

• Start with the exit, not the entry. Whether the plan is sale, refinance or hold decides the product. A cheap bridge with no credible exit is not cheap.
• Be honest about the works. Calling a heavy scheme light to get a quicker answer tends to resurface at drawdown, when it is hardest to fix.
• Lender appetite is uneven. Some lenders know permitted development conversions well; others price them cautiously. Access to a wide range of specialist lenders and private credit, beyond the high street, is what turns a decline into terms.
• Stack only when it earns its place. Where margins are tight, mezzanine or joint venture equity can bridge the gap, but each layer adds cost and intercreditor complexity. Our notes on structuring a development deal when margins are tight go through the trade-offs.

We would rather tell you early that a scheme does not work than arrange something that fails at month nine.

— James William Dawes

Choosing between the two: a practical checklist

Work through these in order.

1. Do you have, or can you get, the right planning route? Permitted development, prior approval or full permission. No clarity means start with a bridge or an option, not a development facility.
2. How heavy are the works? List every structural change, new unit and change of use. If in doubt, assume heavy.
3. What is your track record? Lenders weigh experience heavily on larger conversions and ground-up builds. If you are new, a lighter scheme or a joint venture partner may be the way in.
4. What does VAT do to your appraisal? Ask your accountant to confirm the rate applied to each part of the works.
5. What is the exit, and does it pass? Test sale values or buy-to-let coverage against realistic numbers.
6. What is the contingency? Conversions need room for the unknown. New builds need room for cost movement.
7. Who is monitoring and who is building? Lenders will want a named contractor and, for heavier schemes, a monitoring surveyor.

For wider context on how the options fit together, our overview of types of property finance for UK developers is a good companion.

Working with us

We are a specialist broker for property developers, investors and high-net-worth clients, with a single point of contact from first structuring conversation through to completion. We source from specialist lenders and private credit funds, so a conversion that one lender treats as too risky can be put in front of those that understand it. You can see the panels we work with on our pages for bridging lenders and development lenders, or start a conversation about your scheme through our development finance page.

FAQ

Is it cheaper to finance a conversion or a new build?

There is no fixed answer. Conversions with lighter works can be funded more simply and quickly, but pricing depends on the lender, the planning route and your experience. VAT may favour the new build, since new dwellings are generally zero-rated, whereas qualifying conversions attract 5%.

Can I use a bridging loan for a conversion?

Often yes, particularly for the purchase and lighter works. Heavier schemes with structural changes or additional units tend to need a development facility, either from the start or as a refinance of the bridge. Tell the broker the full scope at the outset so the structure fits.

Does a permitted development conversion get easier finance?

Not automatically. Some lenders are comfortable with permitted development and treat it as lower risk, while others apply cautious planning assumptions across the board. Choosing a lender that knows the route matters more than the route itself.

Can I refinance a finished conversion onto a buy-to-let mortgage?

Possibly, but it is not guaranteed. Buy-to-let lenders apply their own rental coverage tests and property criteria, which differ from development underwriting. Check these before you start works, not after.

Sources

• Buildings and construction (VAT Notice 708), GOV.UK
• VAT refunds for conversions if you’re a DIY housebuilder, GOV.UK
• Reclaim VAT on a self build home, GOV.UK
• When is permission required?, GOV.UK
• Retrospective Building Control approval, Oxford City Council
• Buy-to-let mortgages explained, MoneyHelper
• The development finance problem nobody has quite solved, The Intermediary

Recommended

• The Shifting Development Finance Landscape
• How to Structure a Development Finance Deal When Margins Are Tight
• Nonresident Developer Finance in England: Tax and AML Can Delay Deals